I have read many talkbass build threads in the last 4 years, and have found them extremely helpful. You guys got me thinking about this stuff and you also stimulated me to start 3 builds, the first one almost complete. This first a test bed for this idea I had about how to build a really stable neck. How stable is stable enough? and stiff enough?
Many experienced builders here say that if you make a laminated neck it's fine, no graphite is needed. And if you go to eBay and do a search on "bass neck project" (try it, you'll see a lot of necks!) most are not laminated; they are Leo-style single piece flat sawn maple. So I admit that this build is probably overkill, and just laminating might be fine. But I am planning to keep this bass in India, which is a true test of reliability, since it swings from 115F and less than 10% humidity to 90F and steady 75%+ humidity in the course of a month. So I want to make an indestructible neck.
I often think I have invented something, only to find that a dozen people have had the same thought way before me. So I am not claiming these ideas are unique, but they're new to me and I haven't seen them in TB builds so far. I hope you find them stimulating, at least, and maybe even useful.
Neck design #1 My first design idea was to use a relatively heavy neck wood, like wenge or canarywood, chosen for stiffness, beauty and stability, then to reduce the weight by inlaying a very light wood in what will turn out to be the middle of the neck, like this:
The idea here is that the heavy, dense wood is at the perimeter where it contributes most to strength and stiffness. The softer wood (e.g. white pine, obeche, butternut, sassafras, redwood or unusually light mahogany) gets routed out for the truss rod. Can't be too soft, like balsa, because the truss rod would just dent the balsa. If you think about square steel tubing you see the concept--that you want the stiff material on the outside, and it's stiff even if hollow.
How much weight could you save? I calculated the weight difference between a 57lb/cu ft neck wood and a 27/b/cu ft filler wood for a channel 1 1/4" wide, 3/8" thick and 27" long. The difference came to 3.5 oz or about 98gr. That's actually a decent weight savings, but not as dramatic as saving 98gr in your headstock. Still I imagine you could feel it in reduced neck dive. However, you're going to lose some of that savings by routing out a truss rod channel, so maybe it's not worth the work...
I have a piece of canarywood I'll try this with in an upcoming build. BUT this thread is about the second method I have 'invented,' described next.
Neck design #2. I have already pursued this with a prototype (pictures below), and its build. You make the neck into what I have been thinking of as a "double web I-beam." That's a misnomer because it's the single web that gives an I-beam or H-beam its resemblence to a capital letter and hence its name. So let's just say a double web beam, like this:
In an I-beam the top and bottom flanges give the beam most of its stiffness (according to Wikipedia a least). I reasoned that the fingerboard/fretboard serves as the top flange. Let's give the neck a bottom flange of the same very stiff wood. We provide two webs because we need to reserve the middle for the truss rod. (Of course you could do two truss rods in a wide neck and put one web in the center and really have an I-beam as well). For the web(s) we'll use graphite rectangles. Then we'll fill in the spaces between the webs and between the flanges with the lightest and most stable wood we can find. Here's how our neck turns out in cross section:
As close as possible, the graphite web pieces run all the way from the top web (fretboard) to bottom web. In my first build, at the body end they're 1/8" wide x about 1/2" deep, tapering to about 3/8" deep at the nut.
Now here's an important issue: the graphite webs will completely ignore changes in humidity. The wood filling in the middle of the neck will (if not hermetically sealed) try to move a little with the seasons. So we want to pick a wood with very little expansion/contraction in the dimension that will be epoxied to the graphite. We want to install it flat sawn. Why? because every wood has less movement in the radial direction than the tangential direction, and there will be less tension where the soft wood is glued to the graphite by making it flat sawn, like this:
Note that I chose butternut, soft, light and stable, for the drawing but it is not optimal. Shrinkage against the graphite is decent, but against the fretboard wood it's more movement than most very hard woods (but it would work okay with maple). Mahogany is ideal as a filler wood (more like 2.9%r, 4.3%t) and though I feel guilty about buying it, I have snagged wood from an old dresser whose drawer fronts will make multiple necks for me. And actually it seems there is now farm raised mahogany for sale. If the fretboard is quartersawn wenge its 4.8%r would play very comfortably against the mahogony 4.3%t.
</disclaimer on> I urge people not to get too OCD about matching up movement rates of woods, but I try to take them into account, and not glue flat sawn hard maple (9.9%t) for example to quartersawn teak (2.6%r) and expect them to cooperate without tension and possible instability. Still we all know every board is different and you can only do so much with averages. </disclaimer off>
This neck design approach strongly suggests a flattish D profile rather than a C. For me this is fine because I don't wrap my thumb around the neck--I keep it pretty much centered on the middle of the back of the neck. So I don't mind a broad near-flat area on the back, which is what allows for the wide lower I-beam type of flange--the wenge on the back of the neck. The two flanges make the neck stiff. The graphite contributes to the stiffness as well, and it also really makes the neck stable (in theory).
Next, pictures of the actual neck build, then later the body, etc...
Many experienced builders here say that if you make a laminated neck it's fine, no graphite is needed. And if you go to eBay and do a search on "bass neck project" (try it, you'll see a lot of necks!) most are not laminated; they are Leo-style single piece flat sawn maple. So I admit that this build is probably overkill, and just laminating might be fine. But I am planning to keep this bass in India, which is a true test of reliability, since it swings from 115F and less than 10% humidity to 90F and steady 75%+ humidity in the course of a month. So I want to make an indestructible neck.
I often think I have invented something, only to find that a dozen people have had the same thought way before me. So I am not claiming these ideas are unique, but they're new to me and I haven't seen them in TB builds so far. I hope you find them stimulating, at least, and maybe even useful.
Neck design #1 My first design idea was to use a relatively heavy neck wood, like wenge or canarywood, chosen for stiffness, beauty and stability, then to reduce the weight by inlaying a very light wood in what will turn out to be the middle of the neck, like this:
The idea here is that the heavy, dense wood is at the perimeter where it contributes most to strength and stiffness. The softer wood (e.g. white pine, obeche, butternut, sassafras, redwood or unusually light mahogany) gets routed out for the truss rod. Can't be too soft, like balsa, because the truss rod would just dent the balsa. If you think about square steel tubing you see the concept--that you want the stiff material on the outside, and it's stiff even if hollow.
How much weight could you save? I calculated the weight difference between a 57lb/cu ft neck wood and a 27/b/cu ft filler wood for a channel 1 1/4" wide, 3/8" thick and 27" long. The difference came to 3.5 oz or about 98gr. That's actually a decent weight savings, but not as dramatic as saving 98gr in your headstock. Still I imagine you could feel it in reduced neck dive. However, you're going to lose some of that savings by routing out a truss rod channel, so maybe it's not worth the work...
I have a piece of canarywood I'll try this with in an upcoming build. BUT this thread is about the second method I have 'invented,' described next.
Neck design #2. I have already pursued this with a prototype (pictures below), and its build. You make the neck into what I have been thinking of as a "double web I-beam." That's a misnomer because it's the single web that gives an I-beam or H-beam its resemblence to a capital letter and hence its name. So let's just say a double web beam, like this:
In an I-beam the top and bottom flanges give the beam most of its stiffness (according to Wikipedia a least). I reasoned that the fingerboard/fretboard serves as the top flange. Let's give the neck a bottom flange of the same very stiff wood. We provide two webs because we need to reserve the middle for the truss rod. (Of course you could do two truss rods in a wide neck and put one web in the center and really have an I-beam as well). For the web(s) we'll use graphite rectangles. Then we'll fill in the spaces between the webs and between the flanges with the lightest and most stable wood we can find. Here's how our neck turns out in cross section:
As close as possible, the graphite web pieces run all the way from the top web (fretboard) to bottom web. In my first build, at the body end they're 1/8" wide x about 1/2" deep, tapering to about 3/8" deep at the nut.
Now here's an important issue: the graphite webs will completely ignore changes in humidity. The wood filling in the middle of the neck will (if not hermetically sealed) try to move a little with the seasons. So we want to pick a wood with very little expansion/contraction in the dimension that will be epoxied to the graphite. We want to install it flat sawn. Why? because every wood has less movement in the radial direction than the tangential direction, and there will be less tension where the soft wood is glued to the graphite by making it flat sawn, like this:
Note that I chose butternut, soft, light and stable, for the drawing but it is not optimal. Shrinkage against the graphite is decent, but against the fretboard wood it's more movement than most very hard woods (but it would work okay with maple). Mahogany is ideal as a filler wood (more like 2.9%r, 4.3%t) and though I feel guilty about buying it, I have snagged wood from an old dresser whose drawer fronts will make multiple necks for me. And actually it seems there is now farm raised mahogany for sale. If the fretboard is quartersawn wenge its 4.8%r would play very comfortably against the mahogony 4.3%t.
</disclaimer on> I urge people not to get too OCD about matching up movement rates of woods, but I try to take them into account, and not glue flat sawn hard maple (9.9%t) for example to quartersawn teak (2.6%r) and expect them to cooperate without tension and possible instability. Still we all know every board is different and you can only do so much with averages. </disclaimer off>
This neck design approach strongly suggests a flattish D profile rather than a C. For me this is fine because I don't wrap my thumb around the neck--I keep it pretty much centered on the middle of the back of the neck. So I don't mind a broad near-flat area on the back, which is what allows for the wide lower I-beam type of flange--the wenge on the back of the neck. The two flanges make the neck stiff. The graphite contributes to the stiffness as well, and it also really makes the neck stable (in theory).
Next, pictures of the actual neck build, then later the body, etc...
